Tabbed Urls and Null Values

This doesn't actually affect usability, but maybe something is amiss somewhere else.

When I click on an application at http//creator.zoho.com and it goes to the tabbed layout page, all of the links at the top have null in them, such as

http://creator.zoho.com/flight16/null/Backup%20Views/

However, if I click _any_ link, once the page loads to that tab, the problem will be fixed:

http://creator.zoho.com/flight16/japanese-knowledge/Backup%20Views/

I'm using FireFox 2.0.0.11 on Windows.